The present invention relates to joystick assemblies and, more particularly, to a joystick assembly for use with a keyboard for converting movement of a joystick handle to actuation of selected keys of a keyboard.
Computers are generally provided with a keyboard having at least one set of keys arranged in the format of a typewriter keyboard. To one side of this set of keys, there is normally provided a "numerical key pad" arranged in a common calculator arrangement, i.e., a 3.times.3 pattern for keys corresponding to numbers 1-9. These numerical keys, which are essentially push button switches, have also been adapted to control other functions of the computer. The keys corresponding to numerals 2, 4, 6 and 8 are also utilized as cursor control keys for moving a position cursor on a computer display by one increment, e.g., up or down one line and left or right one position. The keys corresponding to numerals 3 and 9 are also utilized for moving the cursor up and down one page at a time. The keys corresponding to numerals 1 and 7 also serve as "end" and "home" keys for moving a cursor to end and home positions in one move.
It is expected that a computer operator will manipulate these cursor control keys in the same manner as a typist, i.e., by manually depressing a desired key. However, computers are often used in other modes than word processing. In particular, computers are frequently used to create drawings using various CAD programs and more frequently to play various computer games. In these latter modes, movement of the cursor is a primary concern and it is desirable to be able to make such movements without observing finger positions on the keys. While some applications require cursor movements to be controlled by a "mouse" attachment, others, particularly games, allow joysticks to be used. The problem with both the mouse and joystick is that they require separate input cables to the computer and additional hardware for accepting external input.
More recently, it has been proposed to construct a joystick which can be attached to an ordinary keyboard and positioned such that movement of the joystick actuates the cursor control keys. One such joystick is shown in U.S. Pat. No. 4,575,591. The joystick described in this patent requires a panel-like base member attachable to the keyboard frame with a joystick handle attached to the base member and spaced from the keys. A universal mount is attached to the base member and engages the lower end of the handle to allow handle movement in any tiltable direction. Actuating arms are mounted on the base member such that they can be engaged by movement of the handle to force them into contact with the keys. In addition to the relative complexity of this joystick attachment, a relatively large base member is required to be attached to the keyboard. Furthermore, while the above described patent disclosed an attachment for a computer keyboard, it will be recognized that other devices, such as hand-held games, have cursor control keys which would be desirably actuated from a joystick if such could be provided.